Process control systems employ fluid valves to regulate process fluids (e.g., water, natural gas, etc.). A fluid valve typically controls an output flow of a process fluid by moving (e.g., moving via an actuator) a valve plug between different positions relative to a valve seat. To avoid leaks and/or undesired changes in fluid pressure during normal use, certain fluid valves (e.g., sliding stem fluid valves) utilize valve plugs having seals (e.g., O-rings). Such seals can be constructed out of particular materials (e.g., rubber, metal, graphite, etc.) to accommodate different types of fluid control applications, such as supplying feed water to a boiler.